m x n grid in a rectangle, no of rectangles wanted
Source: Flanders Math Olympiad 1987 p1
December 24, 2022
combinatorial geometrycombinatorics
Problem Statement
A rectangle is given. On the side , different points are chosen strictly between and . Similarly, different points are chosen on the side . Lines are drawn from the points parallel to the sides. How many rectangles are formed in this way? (One possibility is shown in the figure.)
https://cdn.artofproblemsolving.com/attachments/0/1/dcf48e4ce318fdcb8c7088a34fac226e26e246.png